Military units often have the need to fire projectiles at high velocities to defeat certain targets. One method of obtaining the high velocities required in these instances has been to use a sub-caliber projectile inside a sabot within a barrel for launching, while ensuring that gas pressure from burning propellant is sealed inside the barrel. The use of a sabot has been in practice since the invention of the firearm. However, many modern sabot designs involve components that fracture during projectile launch to complete the discarding process. Modern sabots are also designed to contain only one penetrator.
An example of a saboted round might be the M903 Saboted Light Armor Penetrator (SLAP) cartridge currently manufactured by Olin-Winchester. That round relies on centrifugal forces and a crush-condition during engraving to shatter the sabot at muzzle exit to initiate discard. During sabot fragmentation, impulse can be transferred to the penetrator causing system accuracy to suffer. It is not capable of launching multiple projectiles without nesting or interaction between the individual components.
Another example of a saboted round is a three-petal sabot design that utilizes a slip ring to decouple the sabot from the gun barrel rifling. This type of sabot is designed to launch fin-stabilized rounds and relies on fracture of the slip ring to initiate discard. The discarding process of that type of sabot can also cause system accuracy to suffer. It also cannot launch multiple projectiles.
A yet further example of a saboted round is a spin-stabilized discarding-sabot projectile. This type of sabot makes use of a metallic pusher combined with a plurality of plastic petals with extended slots or weakening lines. Once again, this type of sabot relies on fracture of sabot hardware to initiate discard, affecting system accuracy. If multiple penetrators were desired, that design would still need to make use of nesting or interaction between the penetrators, hurting accuracy.